WASHINGTON -- Sen. Mary Landrieu, D-La., is part of a diminishing number of Senate Democrats who have not endorsed same-sex marriage. That number is down to just nine among the Senate's 53 Democrats and two independents who caucus with the party, after recent announcements by five Democrats that they support gay marriage.

Landrieu issued a statement Thursday night saying that she'll accept the views of Louisiana voters, though her own have evolved.

"According to the U.S. Constitution,
marriage and family law are reserved for the states," Landrieu said. "The
people of Louisiana
have made clear that marriage in our state is restricted to one man and one
woman. While my personal views have evolved, I will support the outcome of Louisiana's recent vote."

Landrieu was referring to the 2004
referendum when 78 percent of Louisiana
voters approved a constitutional amendment defining marriage as only between a
man and a woman.

The New Orleans-based Forum for Equality, which works for equal rights for gay, lesbian and trans-gender Americans, is expressing patience with Landrieu, whom they praise for opposing a constitutional amendment to ban same-sex marriage and for supporting legislation that bans discrimination based on sexual orientation.

Sen. Mary Landrieu, D-La., is one of nine Senate Democrats who have not endorsed gay marriage.The Associated Press archive

"Forum For Equality realizes the political realities that exist in Louisiana and know Senator Landrieu has been a supporter of equality issues -- from ENDA (Employment Non-discrimination Act) to Don't Ask, Don't Tell," said SarahJane Brady, the group's executive director. "We value her support and appreciate the fact that there is more work to be accomplished here in our home state of Louisiana. We will continue to communicate and educate Senator Landrieu on the importance and impact that marriage equality has on our community and families."

While national polls show a majority of Americans now favor same-sex marriage, a February poll by Public Policy found 59 percent of respondents in Louisiana are opposed, with only 29 percent in support.

On Wednesday, Sen. Kay Hagan, D-N.C., who like Landrieu likely faces a stiff GOP challenge in 2014, announced she supports same-sex marriage. Also endorsing same-sex marriage in recent days were Democrats Jon Tester of Montana, Jay Rockefeller of West Virginia, Claire McCaskill of Missouri and Mark Warner of Virginia.

Here's what Hagan said about the issue in a statement on her Facebook page: "Marriage equality is a complex issue with strong feelings on both sides, and I have a great deal of respect for varying opinions on the issue. After much thought and prayer, I have come to my own personal conclusion that we shouldn't tell people who they can love or who they can marry."

Among Senate Republicans, only Rob Portman of Ohio has embraced same-sex marriage, saying what motivated his change of position is his love for his son, who is gay. His son, he said, should have the right to marry.

"I think you are seeing a change in attitude, a change in tolerance," Murkowski said. "And an acceptance that what marriage should truly be about is a lasting, loving committed relationship with respect to the individual."

Tony Perkins, the former Louisiana legislator who heads the conservative Family Research Council, said any Republican who supports gay marriage would pay a price. Many Americans, he said, just don't consider same-sex marriage to be "natural," and believe children are better off with a household headed by a mother and a father.

"When you look at Republicans, 63 percent of Republicans say it would be harmful to marriage to redefine, to redefine marriage, it would be harmful to the family," Perkins said on "Face the Nation" on Sunday.

But supporters said marriage gives same-sex couples who are in love the opportunities to share in the benefits of marriage without taking anything away from heterosexual couples.

Just a few weeks ago, former President Bill Clinton, who signed the Defense of Marriage Act into law, said he now opposes it. The law bars the federal benefits of marriage to same-sex couples.

The Supreme Court this week held oral arguments on whether the law is constitutional.